BlackBerry squeezed by DoS security bugs

Three vulns but only one fixed

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Research In Motion (RIM) has warned of a trio of vulnerabilities in its popular BlackBerry software that create a means for hackers to launch denial of service attacks. Patches are available to defend against only one of the vulnerabilities, but RIM has issued advice on how to guard against attack from the other two.

The most serious unfixed risk stems from a flaw in processing Server Routing Protocol (SRP) packets. This security bug creates a possible means to disrupt communication between BlackBerry Enterprise Server and BlackBerry Router, potentially disrupting service. A separate unpatched security bug in the handling of malformed Tiff image attachments creates a means for a remote hacker to launch denial of service attacks against the BlackBerry Attachment Service, providing an internal user is duped into viewing malicious files on a BlackBerry handheld.

The vulnerabilities have been reported in BlackBerry Enterprise Server 4.0 as well as later versions. Domino, Exchange and Novell GroupWise versions of the platform are all affected. Exploitation of the first vulnerability means a hacker needs to be able to connect to the BlackBerry Server or Router via port 3101/TCP. Shielding BlackBerry servers behind a firewall ought to thwart these attacks. Additionally, RIM advises users to exclude the processing of Tiff images as a workaround against the second threat, pending the availability of a more complete fix.

A third security bug - for which a fix has been made available - sees a BlackBerry handheld web browser vulnerable to a denial of service via a specially crafted Java Application Description (JAD) file. Users are advised to install BlackBerry device software version 4.0.2 or later to guard against attack.

Details of the vulnerabilities were outlined by FX of the Phenoelit group during a presentation at the 22nd Chaos Communication Congress in Berlin last week. US CERT has produced an overview of the vulnerabilities here.

In a statement, RIM said that it had "already developed software fixes for the issues identified by FX and, although there have been no customer reports of any actual problems, RIM has also provided temporary precautionary measures that can be taken in the meantime until customers are able to implement the software updates". ®